# untested snippet
my @good_lines,@bad_lines;
foreach my $file_name (@file){
    open(MYFILE, $file_name)
      or die qq(Cannot open '$file_name' : $!\n);
    # Read the whole file into memory
    my @lines = <MYFILE>;
    # And find the good and bad lines
    push @good_lines, grep { ! /NOT|INVALID|MUST|ERROR/ }, @lines;
    push @bad_lines,  grep {   /NOT|INVALID|MUST|ERROR/ }, @lines;
};

print "good: @good_lines";
print "bad : @bad_lines";